System, apparatus, and methods for performing a quality diagnostic of an aqueous urea solution

ABSTRACT

System, apparatus, and methods are disclosed for enabling a quality diagnostic of an aqueous urea solution (AUS) of an exhaust system when the AUS is outgassed. Systems, apparatus, and methods are also disclosed for disabling an output of a quality condition of the AUS in response at least in part to detecting that an AUS fill event of an AUS storage tank has occurred.

BACKGROUND

The present application generally relates to an aqueous urea solution (AUS) in internal combustion engine diesel exhaust systems, and more particularly, but not exclusively, to integrating diesel exhaust systems in vehicles.

Modern systems that include internal combustion engines often include a selective catalytic reduction (SCR) exhaust aftertreatment system to control exhaust system emissions. SCR systems typically include an AUS storage tank connected to a doser that injects AUS into the exhaust stream to reduce NOx emissions. Under normal operating conditions, AUS will become depleted from the storage tank and requires periodic re-filling of the storage tank.

An ultrasonic technology quality sensor in the AUS storage tank can be used to measure the fluid density of the AUS to ascertain the concentration quality. However, when AUS is added to the storage tank, potential complications in detecting the quality of the AUS are introduced. Newly added AUS typically stores dissolved gas in the fluid, and micro-bubbles are formed in the AUS when the AUS during operation of the system. This heating causes the dissolved gas to vaporize, resulting in an apparent change to the AUS's physical properties. This apparent physical property change disrupts the speed of sound through the AUS, thereby resulting in incorrect AUS concentration quality readings when using an ultrasonic technology sensor. An incorrect concentration quality reading may result in the system responding in a manner that is detrimental to operation of the engine or the dosing system. As a result of the incorrect quality reading, for example, power to the engine can be reduced or the engine unable to be started altogether. Therefore, a need remains for further improvements in systems, apparatus, and methods for performing a quality diagnostic of an AUS in exhaust aftertreatment systems.

SUMMARY

One embodiment is a unique system, method, and apparatus to determine the outgassed, or offgassed, state of an aqueous urea solution (AUS) in an internal combustion engine diesel exhaust system before enabling a quality diagnostic of the AUS. Other embodiments include unique methods, systems, and apparatus to detect an AUS fill event in an AUS storage tank and to control the performance of an AUS quality diagnostic in view thereof. This summary is provided to introduce a selection of concepts that are further described below in the illustrative embodiments. This summary is not intended to identify key or essential features of the claimed subject matter, nor is it intended to be used as an aid in limiting the scope of the claimed subject matter. Further embodiments, forms, objects, features, advantages, aspects, and benefits shall become apparent from the following description and drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic illustration of a system including an exemplary engine and AUS dosing system.

FIG. 2 is a diagram illustrating an exemplary controller apparatus for controlling an AUS quality diagnostic.

FIG. 3 is a flow diagram of a procedure that can be performed in conjunction with an AUS quality diagnostic.

DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

For the purposes of promoting an understanding of the principles of the invention, reference will now be made to the embodiments illustrated in the drawings and specific language will be used to describe the same. It will nevertheless be understood that no limitation of the scope of the invention is thereby intended, any alterations and further modifications in the illustrated embodiments, and any further applications of the principles of the invention as illustrated therein as would normally occur to one skilled in the art to which the invention relates are contemplated herein.

With reference to FIG. 1, there is illustrated an exemplary system 100 for heating an aqueous urea solution (AUS) that is delivered to an exhaust system 106 of an engine 102 via a dosing system 120. AUS stored in an AUS storage tank 132 is delivered to an aftertreatment system 126 of an engine 102 from an AUS dosing system 120. System 100 may be provided on a vehicle powered by an engine 102 such as a diesel engine, or on an engine 102 utilized in other applications such as power generation or pumping systems. Engine 102 includes an intake system 104 through which charge air enters and an exhaust system 106 through which exhaust gas resulting from combustion exits, it being understood that not all details of these systems that are typically present are shown. Engine 102 includes a number of cylinders forming combustion chambers into which fuel is injected by fuel injectors to combust with the charge air that has entered through intake system 104. The energy released by combustion powers the engine 102 via pistons connected to a crankshaft. When used to propel a vehicle, engine 102 is coupled through a drivetrain to drive wheels that propel the vehicle. Intake valves control the admission of charge air into the cylinders, and exhaust valves control the outflow of exhaust gas through exhaust system 106 and ultimately to atmosphere. Before entering the atmosphere, however, the exhaust gas is treated by one or more aftertreatment devices in an aftertreatment system 126.

In one example, the exhaust system 106 includes an aftertreatment system 126 having one or more selective catalytic reduction (SCR) catalysts 128 and one or more locations for receiving an AUS from AUS dosing system 120. The aftertreatment system 126 may include one or more other aftertreatment components not shown, such as one or more oxidation catalysts, one or more particulate filters, an ammonia oxidation catalyst, and various temperature, pressure and exhaust gas constituent sensors. Exhaust system 106 may also include various components not shown, such an exhaust gas recirculation system, a turbocharger system, coolers, and other components connecting exhaust system 106 to intake system 104. An AUS injector 124 is mounted on a portion of exhaust system 106 upstream of SCR catalyst 128 with its outlet, or nozzle, arranged to spray AUS into the exhaust system 106 where it mixes with engine exhaust gas produced by engine 102. SCR catalyst 128 promotes a chemical reaction between the AUS and NOx in the exhaust gas that converts substantial amounts of NOx to reduce NOx emissions before the exhaust gas passes into the atmosphere.

Dosing system 120 receives AUS from an AUS storage tank 132 and provides the AUS to the exhaust system 106 via an injector 124 or other structure for injection or delivery to a decomposition chamber or directly to the exhaust system 106. The flow of AUS through injector 124 can controlled by a dosing system two-way control valve 122 or other structure for toggling or limiting AUS flow to the injector 124. As used herein, injector includes any nozzle, static device, electronically controllable device, and/or mechanical actuator that provide an outlet for reductant delivery. One example of an AUS is a diesel exhaust fluid (DEF) which comprises a solution of 32.5% high purity urea and 67.5% deionized water. It shall be appreciated, however, that other aqueous urea solutions may also be utilized.

Dosing system 120 may include various structures to facilitate receipt of AUS from an AUS storage tank 132 and the delivery of the AUS to the exhaust system 106. For example, a dosing system may include a pump and a filter screen and a check valve upstream of the pump to receive AUS from the AUS storage tank 132.

AUS storage tank 132 holds a supply of AUS and is vented to allow AUS to be withdrawn at an outlet port 134. When dosing system 124 operates, it draws AUS from AUS storage tank 132 and pumps the AUS through conduit 136 to injector 124. A backflow conduit (not shown) may be provided to return excess AUS to AUS storage tank 132.

In certain embodiments, the system 100 further includes a controller 160 structured to perform certain operations to receive and interpret signals from an AUS temperature sensor 152, an AUS storage tank 132 level sensor 154, and an AUS quality sensor 156, which can be position inside the tank 132. In certain embodiments, the controller forms a portion of a processing subsystem including one or more computing devices having memory, processing, and communication hardware. The controller may be a single device or a distributed device, and the functions of the controller may be performed by hardware or software.

Engine 102 further comprises a heat exchange system 140 through which a heat exchange fluid, such as engine coolant, is circulated by a pump 108. A conduit 114 forms at least a portion of a heat exchange circuit 142 that defines a flow path for the heated heat exchange fluid to flow though dosing system 120 and AUS storage tank 132 to heat AUS therein by providing thermal contact of the heat exchange fluid with the AUS located in AUS storage tank 132. Heat exchange system 140 receives heat from a heat source, such as engine 102, that heats the heat exchange fluid in or before it enters heat exchange circuit 142. Heat exchange system 140 may be part of the cooling system for engine 102 that is connected to a radiator (not shown) that receives and rejects heat generated by operation of engine 102. Other embodiments contemplate heat sources other than or in addition to engine 102, such as the exhaust system, an electric heater, or other source of heat that maintains or rapidly heats the heat exchange fluid for use in heating AUS. Furthermore, it is contemplated that fluids other than liquid coolant may be used as the heat exchange fluid.

In the illustrated embodiment, the continuous flow path defined by the heat exchange circuit 142 extends from an outlet 110 of pump 108 to a storage tank inlet 136 of AUS storage tank 132, and through AUS storage tank 132. A return portion 144 of the flow of the conduit 114 path extends from the second storage tank outlet 138 of the AUS storage tank 132 to the inlet 112 of pump 108 and includes, for example, a heat exchange two-way control valve 116 in the flow path between the outlet 138 of AUS storage tank 132 and the inlet 112 of pump 112. Conduit 114 may be comprised of a single continuous conduit or multiple conduits through AUS storage tank 132, or of discrete segments connected to inlets and outlets of AUS storage tank 132, with channels, conduits or other structures that provide a continuation of the flow path therethrough.

The flow of heat exchange fluid in heat exchange circuit 136 may be controlled and monitored by controller 160 such as an engine control module (ECM) or a doser control module (DCM). It shall be appreciated that the controller or control module may be provided in a variety of forms and configurations including one or more computing devices forming a whole or part of a processing subsystem having non-transitory memory storing computer executable instructions, processing, and communication hardware.

Controller 160 is in communication with any component of the system 100 to gather information and provide commands. In FIG. 1, controller 160 is operatively coupled with and configured to store instructions in a memory which are readable and executable by controller 160 to operate heat exchange control valve 116 to complete one or more heat exchange cycles that heat an AUS in AUS storage tank 132. Controller 160 is further operatively coupled with and may receive a signal from AUS temperature sensor 152, AUS level sensor 154, and AUS quality sensor 156 associated with AUS storage tank 132. AUS temperature sensor 152 is operable to provide a signal indicating the temperature of the AUS in AUS storage tank 132. AUS level sensor 154 is operable to provide a signal indicating the level of the AUS in AUS storage tank 132. AUS quality sensor 156 is operable to provide a signal indicating the quality of the AUS in AUS storage tank 132. AUS temperature sensor 152, AUS level sensor 154, and AUS quality sensor 156 need not be in direct communication with AUS storage tank 132, and can be located at any position within AUS outgassing system 130 that provides a suitable indication of applicable AUS readings in AUS storage tank 132.

In FIG. 1, controller 160 is further connected to dosing system 120, dosing system two-way control valve 122, heat exchange two-way control valve 116, and an AUS quality fault output 158. AUS quality fault output 158 can be any suitable device for displaying a result of the AUS quality diagnostic to a user, operator, service technician, or other party, and can include an indicator lamp, a gauge, a printer, a memory device, an audible alarm, and/or other suitable output device.

The controller 160 includes stored data values, constants, and functions, as well as operating instructions stored on computer readable medium. Any of the operations of exemplary procedures described herein may be performed at least partially by the controller. The description herein including modules emphasizes the structural independence of the aspects of the controller 160, and illustrates one grouping of operations and responsibilities of the controller 160. Other groupings that execute similar overall operations are understood within the scope of the present application. Modules may be implemented in hardware and/or software on computer readable medium, and modules may be distributed across various hardware or software components. More specific descriptions of certain embodiments of controller operations are included in the section referencing FIG. 2. Operations illustrated are understood to be exemplary only, and operations may be combined or divided, and added or removed, as well as re-ordered in whole or part, unless stated explicitly to the contrary herein.

Certain operations described herein include operations to interpret one or more parameters. Interpreting, as utilized herein, includes receiving values by any method known in the art, including at least receiving values from a datalink or network communication, receiving an electronic signal (e.g., a voltage, frequency, current, or PWM signal) indicative of the value, receiving a software parameter indicative of the value, reading the value from a memory location on a computer readable medium, receiving the value as a run-time parameter by any means known in the art, and/or by receiving a value by which the interpreted parameter can be calculated, and/or by referencing a default value that is interpreted to be the parameter value.

One exemplary embodiment of controller 160 is shown in FIG. 2. In certain embodiments, the controller 160 includes an AUS quality input 172 that is received as a signal from AUS quality sensor 156, an AUS level input 182 that is received as a signal from AUS level sensor 154, and an AUS temperature input 192 that is received as a signal from AUS temperature sensor 152. In certain embodiments, the controller 160 includes one or more modules structured to functionally execute the operations of the controller 160 in response to the inputs 172, 182, and 192.

Controller 160 includes an AUS quality module 170 that receives and interprets the AUS quality input 172. AUS quality module 170 is configured to output an AUS quality condition 174 that indicates a quality of the AUS in AUS storage tank 132. When a fault condition of the AUS quality is determined, operation of engine 102 may be derated or other system impacting restraint may be initiated to limit operation with AUS that is not of a predetermined or desired quality.

The controller 160 further includes an AUS storage tank level module 180 that receives and interprets AUS level input 182. The AUS level input provides an indication of the AUS level in AUS storage tank 132. AUS storage tank level module 180 is configured to provide a tank fill level indication 184 when a comparison of AUS level input 182 signals indicates an AUS storage tank 132 fill event has occurred, which indicates dissolved gasses are present in the AUS in AUS storage tank 132 which is detrimental to AUS quality determination.

Controller 160 also includes an AUS outgassing module 190 that receives and interprets an AUS temperature input 192. Furthermore, the AUS outgassing module 190 interprets a tank fill indication 184 from the AUS storage tank level module 180. When a tank fill indication 184 indicates a re-fill or filling event of storage tank 132 has occurred, AUS outgassing module suspends operation of an AUS quality determination by AUS quality module 170 and performs an operation such as providing an AUS heating command 196 to outgas the AUS in storage tank 132. In one embodiment, in response to AUS heating command 196, controller 160 provides a signal to open heat exchange valve 116 to initiate circulation of the heat exchange fluid to heat the AUS in AUS storage tank 132, which vaporizes the dissolved gas in the AUS so that an accurate AUS quality input 172 can be provided.

AUS outgassing module 190 is further configured to provide an AUS quality determination command 194 to enable a determination of the quality of the AUS when the AUS heating operation initiated by AUS heating command 196 is satisfied. In one embodiment, satisfaction of AUS heating command 196 is determined by AUS temperature input 192 indicating a predetermined temperature increase of the AUS in AUS storage tank 132, the temperature of the AUS in AUS storage tank 132 reaching a predetermined temperature differential threshold 191, by providing heating for a predetermined amount of time, or other outgassing indication. The AUS quality determination command 194 is interpreted by the AUS quality module 170 to enable providing of AUS quality condition 174 from AUS quality input 172. In certain embodiments, the controller 160 and/or the AUS outgassing module 190 contain a timer mechanism (not shown) operable in conjunction with AUS temperature input 192 for interpreting an outgassing period or providing an outgassed indication.

The schematic flow diagram in FIG. 3 and related description which follows provides an illustrative embodiment of performing procedures for enabling a quality diagnostic based on an AUS outgassing determination. Operations illustrated are understood to be exemplary only, and operations may be combined or divided, and added or removed, as well as re-ordered in whole or part, unless stated explicitly to the contrary herein. Certain operations illustrated may be implemented by a computer executing a computer program product on a non-transient computer readable storage medium, where the computer program product comprises instructions causing the computer to execute one or more of the operations, or to issue commands to other devices to execute one or more of the operations.

With reference to FIG. 3, there is illustrated a flow diagram of an exemplary procedure 200 for enabling a quality diagnostic that is put in operation by programming into controller 160 for use in, for example, system 100. Procedure 200 begins at operation 202 in which a control routine for enabling an AUS quality diagnostic is started. Operation 202 can begin by interpreting a key-on event and/or by initiation by an operator or technician. Operation 202 may alternatively or additionally include interpreting a communication or other parameter indicating that operation of the AUS quality determination is going to resume after an AUS outgassing procedure. Procedure 200 proceeds at operation 204, where the AUS level in storage tank 132 is interpreted. From operation 204, procedure 200 proceeds at conditional 206 where it is determined whether a storage tank fill event has occurred since the AUS was last outgassed. If conditional 206 is negative, procedure 200 proceeds at operation 212 where an AUS quality diagnostic is performed until a termination condition at 214.

If conditional 206 is affirmative, procedure 200 continues at conditional 208 where it is determined whether the AUS is outgassed. In one embodiment, the determination whether the AUS is outgassed includes determining whether the AUS has experienced a sufficient temperature rise to outgas the AUS since a most recent AUS fill event of the storage tank. In certain embodiments, the sufficient temperature rise can include the AUS being heated at a certain temperature for at least 30 minutes, being heated to a temperature at least 30° C. above a fill temperature, and being heated to a temperature of at least 45° C. If conditional 208 is affirmative, procedure 200 proceeds at operation 212 where an AUS quality diagnostic is performed until a termination condition at 214.

If conditional 208 is negative, procedure 200 proceeds at operation 210 to outgas the AUS before enabling the AUS quality diagnostic. In one embodiment of operation 210, the AUS in AUS storage tank 132 is heated until a termination condition is reached which indicates the AUS is outgassed, or until another heat cycle is initiated at conditional 208. Procedure 200 then continues as discussed above to complete one or more cycles at operation 210 to heat the AUS by, for example, circulation of the heat exchange fluid until the AUS in the storage tank has been outgassed.

In certain embodiments, the AUS in AUS storage tank 132 is determined to be outgassed when the AUS reaches a predetermined temperature T_(x), has been heated to increase in temperature by a predetermined temperature differential threshold T_(th) 191, and/or has been maintained at a predetermined threshold temperature for a predetermined period of time t_(x). In certain specific embodiments, the AUS is outgassed by at least one of the following: heating the AUS for at least 30 minutes, heating the AUS to a temperature rise of at least 30° C., and heating the AUS to a temperature of at least 45° C.

Various aspects of the systems, apparatus, and methods disclosed herein. For example, one aspect involves a method that includes determining that an aqueous urea solution AUS confined in a storage tank that is connected to an exhaust system is outgassed and, in response to the determining the AUS is outgassed, performing an AUS diagnostic comprising operating a quality sensor to determine a urea concentration of the AUS. Operating the urea quality sensor comprises ultrasonically determining a fluid density of the AUS.

In one embodiment, the method includes, in response to determining the AUS is not outgassed, disabling the performing the AUS diagnostic. In one refinement, the method includes, in response to determining the AUS is not outgassed, operating a heater to increase a temperature of the AUS. In a further refinement of the method, operating the heater includes heating the AUS according to at least one operation selected from the operations consisting of: heating the AUS for at least 30 minutes, heating the AUS to a temperature rise of at least 30° C., and heating the AUS to a temperature of at least 45° C. In another refinement of the method, the operating the heater includes opening a heat exchange valve in a heat exchange system that receives heat from operation of an internal combustion engine. In another embodiment of the method, determining that the AUS confined in the storage tank is outgassed includes determining whether the AUS has experienced a sufficient temperature rise since a most recent AUS fill event of the storage tank. The sufficient temperature rise can include at least one event selected from the events consisting of: being heated for at least 30 minutes, being heated to a temperature at least 30° C. above a fill temperature, and being heated to a temperature of at least 45° C.

In another aspect, a method includes detecting a fill event of a storage tank for storing an AUS; disabling a quality diagnostic of the AUS after detecting the fill event; and outgassing the AUS before enabling the quality diagnostic.

In one embodiment of the method, after outgassing the AUS, the method includes performing an AUS diagnostic by operating a quality sensor to determine a urea concentration of the AUS by ultrasonically determining a fluid density of the AUS. In one refinement, outgassing the AUS includes at least one operation selected from the operations consisting of: heating the AUS for at least 30 minutes, heating the AUS to a temperature rise of at least 30° C., and heating the AUS to a temperature of at least 45° C. In another refinement of the method, heating the AUS includes opening a heat exchange valve of a heat exchange circuit to circulate a heat exchange fluid that is heated by operation of an internal combustion engine to the storage tank. In another embodiment, detecting the fill event includes determining whether an AUS level in the storage tank has increased since a last known fill level detection.

In another aspect, an apparatus includes an electronic controller connected to an AUS storage tank level sensor and an AUS quality sensor associated with an AUS storage tank for providing AUS to an exhaust system. The controller is further connected to a heating device and includes a storage tank level determination module configured to detect a fill event of AUS in the storage tank, a quality determination module configured to determine a quality of the AUS in the storage tank and output a quality condition associated with the quality of the AUS, and an AUS outgassing module configured to disable output of the quality condition by the quality determination module upon the detection of the fill event by the storage tank level determination module. The AUS outgassing module is further configured to control the heating device to increase a temperature of the AUS a predetermined amount before enabling output of the quality condition by the quality determination module.

In one embodiment, the heating device includes a heat exchange circuit that provides a flow of heating fluid to the storage tank for heating of the AUS. In another embodiment, the quality determination module is configured to output to a display an indication of the AUS quality.

According to another aspect, a system includes an internal combustion engine including an exhaust system; a dosing system connected to the exhaust system to provide AUS to the exhaust system; and a storage tank for storing AUS connected to the dosing system The storage tank includes a level sensor operable to indicate a level of AUS in the storage tank, a quality sensor operable to indicate a quality condition of the AUS in the storage tank, and a temperature sensor operable to indicate a temperature of the AUS in the storage tank. The system also includes a heat exchange system configured to heat the AUS and a controller connected to the heat exchange system that is operable to control heating of the AUS in the storage tank. The controller is configured to suspend an output of the indication of the quality condition of the AUS and increase a temperature of the AUS a predetermined amount in response at least in part to an indication from the level sensor that the level of AUS in the storage tank has increased.

In one embodiment, the heat exchange system defines a flow path that is arranged to circulate a heat exchange fluid to thermally contact heated heat exchange fluid with the AUS in the storage tank. The heat exchange system further includes a control valve in the flow path to control a flow of the heat exchange fluid in the flow path. In one refinement, the controller is configured to initiate a circulation period of the heated heat exchange fluid in the flow path through the storage tank to increase the temperature of the AUS in the storage tank the predetermined amount. In a further refinement, the predetermined amount includes at least one of the AUS being heated to a temperature threshold, an increase in temperature of the AUS by a predetermined amount, and a heating the AUS at a predetermined temperature for a length of time.

While the invention has been illustrated and described in detail in the drawings and foregoing description, the same is to be considered as illustrative and not restrictive in character, it being understood that only certain exemplary embodiments have been shown and described. Those skilled in the art will appreciate that many modifications are possible in the example embodiments without materially departing from this invention. Accordingly, all such modifications are intended to be included within the scope of this disclosure as defined in the following claims.

In reading the claims, it is intended that when words such as “a,” “an,” “at least one,” or “at least one portion” are used there is no intention to limit the claim to only one item unless specifically stated to the contrary in the claim. When the language “at least a portion” and/or “a portion” is used the item can include a portion and/or the entire item unless specifically stated to the contrary. 

What is claimed is:
 1. A method, comprising: determining that an aqueous urea solution (AUS) confined in a storage tank that is connected to an exhaust system is outgassed; in response to the determining the AUS is outgassed, performing an AUS diagnostic comprising operating a quality sensor to determine a urea concentration of the AUS; wherein the operating the urea quality sensor comprises ultrasonically determining a fluid density of the AUS.
 2. The method of claim 1, further comprising, in response to determining the AUS is not outgassed, disabling the performing the AUS diagnostic.
 3. The method of claim 2, further comprising, in response to determining the AUS is not outgassed, operating a heater to increase a temperature of the AUS.
 4. The method of claim 3, wherein the operating the heater comprises heating the AUS according to at least one operation selected from the operations consisting of: heating the AUS for at least 30 minutes, heating the AUS to a temperature rise of at least 30° C., and heating the AUS to a temperature of at least 45° C.
 5. The method of claim 3, wherein the operating the heater comprises opening a heat exchange valve in a heat exchange system that receives heat from operation of an internal combustion engine.
 6. The method of claim 1, wherein the determining that the AUS confined in the storage tank is outgassed comprises determining whether the AUS has experienced a sufficient temperature rise since a most recent AUS fill event of the storage tank, wherein the sufficient temperature rise comprises at least one event selected from the events consisting of: being heated for at least 30 minutes, being heated to a temperature at least 30° C. above a fill temperature, and being heated to a temperature of at least 45° C.
 7. A method, comprising: detecting a fill event of a storage tank for storing an aqueous urea solution (AUS); disabling a quality diagnostic of the AUS after detecting the fill event; and outgassing the AUS before enabling the quality diagnostic.
 8. The method of claim 7, after outgassing the AUS, performing an AUS diagnostic comprising operating a quality sensor to determine a urea concentration of the AUS; wherein the operating the urea quality sensor comprises ultrasonically determining a fluid density of the AUS.
 9. The method of claim 8, wherein outgassing the AUS includes at least one operation selected from the operations consisting of: heating the AUS for at least 30 minutes, heating the AUS to a temperature rise of at least 30° C., and heating the AUS to a temperature of at least 45° C.
 10. The method of claim 8, wherein heating the AUS comprises opening a heat exchange valve of a heat exchange circuit to circulate a heat exchange fluid that is heated by operation of an internal combustion engine to the storage tank.
 11. The method of claim 7, wherein detecting the fill event comprises determining whether an AUS level in the storage tank has increased since a last known fill level detection.
 12. An apparatus, comprising: an electronic controller connected to an aqueous urea solution (AUS) storage tank level sensor and an AUS quality sensor associated with an AUS storage tank for providing AUS to an exhaust system, wherein the controller is further connected to a heating device and includes: a storage tank level determination module configured to detect a fill event of AUS in the storage tank; a quality determination module configured to determine a quality of the AUS in the storage tank and output a quality condition associated with the quality of the AUS; and an AUS outgassing module configured to disable output of the quality condition by the quality determination module upon the detection of the fill event by the storage tank level determination module, where the AUS outgassing module is further configured to control the heating device to increase a temperature of the AUS a predetermined amount before enabling output of the quality condition by the quality determination module.
 13. The apparatus of claim 12, wherein the heating device includes a heat exchange circuit that provides a flow of heating fluid to the storage tank for heating of the AUS.
 14. The apparatus of claim 12, wherein the quality determination module is configured to output to a display an indication of the AUS quality.
 15. A system, comprising: an internal combustion engine including an exhaust system; a dosing system connected to the exhaust system to provide an aqueous urea solution (AUS) to the exhaust system; a storage tank for storing AUS connected to the dosing system, wherein the storage tank includes a level sensor operable to indicate a level of AUS in the storage tank, a quality sensor operable to indicate a quality condition of the AUS in the storage tank, and a temperature sensor operable to indicate a temperature of the AUS in the storage tank; a heat exchange system configured to heat the AUS; and a controller connected to the heat exchange system that is operable to control heating of the AUS in the storage tank, wherein the controller is configured to suspend an output of the indication of the quality condition of the AUS and increase a temperature of the AUS a predetermined amount in response at least in part to an indication from the level sensor that the level of AUS in the storage tank has increased.
 16. The system of claim 15, wherein the heat exchange system defines a flow path that is arranged to circulate a heat exchange fluid to thermally contact heated heat exchange fluid with the AUS in the storage tank, wherein the heat exchange system further includes a control valve in the flow path to control a flow of the heat exchange fluid in the flow path.
 17. The system of claim 16, wherein the controller is configured to initiate a circulation period of the heated heat exchange fluid in the flow path through the storage tank to increase the temperature of the AUS in the storage tank the predetermined amount.
 18. The system of claim 17, wherein the predetermined amount includes at least one of the AUS being heated to a temperature threshold, an increase in temperature of the AUS by a predetermined amount, and a heating the AUS at a predetermined temperature for a length of time. 